/*  _______         ____    __         ___    ___
 * \    _  \       \    /  \  /       \   \  /   /       '   '  '
 *  |  | \  \       |  |    ||         |   \/   |         .      .
 *  |  |  |  |      |  |    ||         ||\  /|  |
 *  |  |  |  |      |  |    ||         || \/ |  |         '  '  '
 *  |  |  |  |      |  |    ||         ||    |  |         .      .
 *  |  |_/  /        \  \__//          ||    |  |
 * /_______/ynamic    \____/niversal  /__\  /____\usic   /|  .  . ibliotheque
 *                                                      /  \
 *                                                     / .  \
 * resamp2.inc - Resampling helper template.          / / \  \
 *                                                   | <  /   \_
 * By Bob and entheh.                                |  \/ /\   /
 *                                                    \_  /  > /
 * In order to find a good trade-off between            | \ / /
 * speed and accuracy in this code, some tests          |  ' /
 * were carried out regarding the behaviour of           \__/
 * long long ints with gcc. The following code
 * was tested:
 *
 * int a, b, c;
 * c = ((long long)a * b) >> 16;
 *
 * DJGPP GCC Version 3.0.3 generated the following assembly language code for
 * the multiplication and scaling, leaving the 32-bit result in EAX.
 *
 * movl  -8(%ebp), %eax    ; read one int into EAX
 * imull -4(%ebp)          ; multiply by the other; result goes in EDX:EAX
 * shrdl $16, %edx, %eax   ; shift EAX right 16, shifting bits in from EDX
 *
 * Note that a 32*32->64 multiplication is performed, allowing for high
 * accuracy. On the Pentium 2 and above, shrdl takes two cycles (generally),
 * so it is a minor concern when four multiplications are being performed
 * (the cubic resampler). On the Pentium MMX and earlier, it takes four or
 * more cycles, so this method is unsuitable for use in the low-quality
 * resamplers.
 *
 * Since "long long" is a gcc-specific extension, we use LONG_LONG instead,
 * defined in dumb.h. We may investigate later what code MSVC generates, but
 * if it seems too slow then we suggest you use a good compiler.
 *
 * FIXME: these comments are somewhat out of date now.
 */

#define SUFFIX3 _1

/* For convenience, returns nonzero on stop. */
static int process_pickup(DUMB_RESAMPLER *resampler) {
    if (resampler->overshot < 0) {
        resampler->overshot = 0;
        dumb_resample(resampler, NULL, 2, MONO_DEST_VOLUME_ZEROS,
                      1.0f); /* Doesn't matter which SUFFIX3. */
        COPYSRC(resampler->X, 0, resampler->X, 1);
    }

    for (;;) {
        SRCTYPE *src = resampler->src;

        if (resampler->dir < 0) {
            if (resampler->overshot >= 3 &&
                resampler->pos + 3 >= resampler->start)
                COPYSRC(resampler->X, 0, src, resampler->pos + 3);
            if (resampler->overshot >= 2 &&
                resampler->pos + 2 >= resampler->start)
                COPYSRC(resampler->X, 1, src, resampler->pos + 2);
            if (resampler->overshot >= 1 &&
                resampler->pos + 1 >= resampler->start)
                COPYSRC(resampler->X, 2, src, resampler->pos + 1);
            resampler->overshot = (int)(resampler->start - resampler->pos - 1);
        } else {
            if (resampler->overshot >= 3 && resampler->pos - 3 < resampler->end)
                COPYSRC(resampler->X, 0, src, resampler->pos - 3);
            if (resampler->overshot >= 2 && resampler->pos - 2 < resampler->end)
                COPYSRC(resampler->X, 1, src, resampler->pos - 2);
            if (resampler->overshot >= 1 && resampler->pos - 1 < resampler->end)
                COPYSRC(resampler->X, 2, src, resampler->pos - 1);
            resampler->overshot = (int)(resampler->pos - resampler->end);
        }

        if (resampler->overshot < 0) {
            resampler->overshot = 0;
            return 0;
        }

        if (!resampler->pickup) {
            resampler->dir = 0;
            return 1;
        }
        (*resampler->pickup)(resampler, resampler->pickup_data);
        if (resampler->dir == 0)
            return 1;
        ASSERT(resampler->dir == -1 || resampler->dir == 1);
    }
}

/* Create mono destination resampler. */
/* SUFFIX3 was set above. */
#define VOLUME_PARAMETERS MONO_DEST_VOLUME_PARAMETERS
#define VOLUME_VARIABLES MONO_DEST_VOLUME_VARIABLES
#define SET_VOLUME_VARIABLES SET_MONO_DEST_VOLUME_VARIABLES
#define RETURN_VOLUME_VARIABLES RETURN_MONO_DEST_VOLUME_VARIABLES
#define VOLUMES_ARE_ZERO MONO_DEST_VOLUMES_ARE_ZERO
#define PEEK_FIR MONO_DEST_PEEK_FIR
#define MIX_FIR MONO_DEST_MIX_FIR
#define MIX_ZEROS(op) *dst++ op 0
#include "resamp3.inc"

/* Create stereo destination resampler. */
#define SUFFIX3 _2
#define VOLUME_PARAMETERS                                                      \
    DUMB_VOLUME_RAMP_INFO *volume_left, DUMB_VOLUME_RAMP_INFO *volume_right
#define VOLUME_VARIABLES                                                       \
    lvol, lvolr, lvold, lvolt, lvolm, rvol, rvolr, rvold, rvolt, rvolm
#define SET_VOLUME_VARIABLES                                                   \
    {                                                                          \
        if (volume_left) {                                                     \
            lvolr = volume_left->volume;                                       \
            lvold = volume_left->delta;                                        \
            lvolt = volume_left->target;                                       \
            lvolm = volume_left->mix;                                          \
            lvol = lvolr * lvolm;                                              \
            if (lvolr == lvolt)                                                \
                volume_left = NULL;                                            \
        } else {                                                               \
            lvol = 0;                                                          \
            lvold = 0;                                                         \
            lvolt = 0;                                                         \
            lvolm = 0;                                                         \
        }                                                                      \
        if (volume_right) {                                                    \
            rvolr = volume_right->volume;                                      \
            rvold = volume_right->delta;                                       \
            rvolt = volume_right->target;                                      \
            rvolm = volume_right->mix;                                         \
            rvol = rvolr * rvolm;                                              \
            if (rvolr == rvolt)                                                \
                volume_right = NULL;                                           \
        } else {                                                               \
            rvol = 0;                                                          \
            rvold = 0;                                                         \
            rvolt = 0;                                                         \
            rvolm = 0;                                                         \
        }                                                                      \
    }
#define RETURN_VOLUME_VARIABLES                                                \
    {                                                                          \
        if (volume_left)                                                       \
            volume_left->volume = lvolr;                                       \
        if (volume_right)                                                      \
            volume_right->volume = rvolr;                                      \
    }
#define VOLUMES_ARE_ZERO (lvol == 0 && lvolt == 0 && rvol == 0 && rvolt == 0)
#define PEEK_FIR STEREO_DEST_PEEK_FIR
#define MIX_FIR STEREO_DEST_MIX_FIR
#define MIX_ZEROS(op)                                                          \
    {                                                                          \
        *dst++ op 0;                                                           \
        *dst++ op 0;                                                           \
    }
#include "resamp3.inc"

#undef MONO_DEST_VOLUMES_ARE_ZERO
#undef SET_MONO_DEST_VOLUME_VARIABLES
#undef RETURN_MONO_DEST_VOLUME_VARIABLES
#undef MONO_DEST_VOLUME_ZEROS
#undef MONO_DEST_VOLUME_VARIABLES
#undef MONO_DEST_VOLUME_PARAMETERS
#undef MONO_DEST_PEEK_FIR
#undef STEREO_DEST_PEEK_FIR
#undef MONO_DEST_MIX_FIR
#undef STEREO_DEST_MIX_FIR
#undef ADVANCE_FIR
#undef POKE_FIR
#undef COPYSRC2
#undef COPYSRC
#undef DIVIDE_BY_SRC_CHANNELS
#undef SRC_CHANNELS
#undef SUFFIX2
